PETpla.net Insider 04 / 2012

MATERIAL / RECYCLING 13 PET planet insider Vol. 13 No. 04/12 www.petpla.net that simultaneously meets the require- ments of both organisations. Protocol specifics The APR calls its series of primary testing protocols the Critical Guid- ance and Applications Guidance Documents . The EPBP’s version is called the PET Recycling Test Proto- col . (Additionally, both organisations provide design guidelines to help mini- mise future recycle stream impact.) Materials to be evaluated in these studies can include a new PET resin, an additive, bottle coating, barrier resin, or even a label adhesive for a package. To start the process, blown bottles, also referred to as the “inno- vation bottles,” are ground. Primary steps of the protocols The flow chart below outlines the primary steps that are performed in each of the recycle protocols. Bottle grinding / flaking The simple task of grinding the bottle flake for each study is slightly different due to the allowable grind size for each protocol. Although some might think that this makes very little difference, a smaller flake grind size can increase the amount of fines pro- duced. In a multilayer structure, it can result in more separation. When evaluating a multilayer bottle, the smaller flake grind (which is suggested in the APR protocol) can aid in the separation of the middle layer from the PET. These requirements allow for a ground flake size that can range from a nominal 6.35mm to 12.7mm, while the EPBP protocol simply calls for a 12mm screen size. Pre-wash air elutriation Air elutriation is the next suggested step in the U.S. protocol. Performed before washing, air elutriation will remove “lights” (labels) or thin mul- tilayer materials. Depending on the type of innovation being studied, this step may not be relevant and can be skipped if the application warrants it. However its inclusion can be important in studies evaluating multilayer resins or even labels. The European test pro- tocol does not call for this first elutria- tion of the ground flake materials. Flake washing Washing the flake is an important and critical step in both protocols. There are a wide variety of wash systems in use today, and one may believe the differences are not crucial but in fact they can be significant. A laboratory wash process has been developed that simulates what is cur- rently in commercial use. Both the APR and the EPBP wash protocols are similar when both use aggressive hot caustic washes. Testing the solution intrinsic viscosity of rPET s HIGHER DIMENSION STABILITY AFTER EJECTION s LOW RESIDUAL HEAT WITHIN THE PACKAGING s EQUAL TEMPERATURE PROFILE OF ALL PARTS s LOW ENERGY CONSUMPTION WUHRMÜHLE 22 A-6840 GÖTZIS T +43 5523 55558-0 COOL@EISBAER.AT WWW.EISBAER.AT